This invention relates to handheld calculators, and more particularly to an interface for reformatting calculator display signals so that they are suitable for display on a television and also for adding additional content to the display, such as input from a pointing device or a display of the calculator keypad.
Electronic calculators have become an essential tool for everyone. Consumers have a wide choice of calculator types and models.
Many persons own relatively inexpensive scientific calculators with one or two line displays, but recently more and more persons are discovering the advantages of xe2x80x9cbig-screenxe2x80x9d calculators characterized by a two-dimensional display screen capable of displaying graphs and other graphical images. These calculators are often called xe2x80x9cgraphing calculatorsxe2x80x9d because the popularity of these calculators for use in teaching various types of graphs and plots.
Calculators with these larger display screens are especially popular for educational applications. When these calculators are used in a classroom, it is often desired to duplicate the calculator display on an even larger screen suitable for viewing by an entire room full of students. The conventional approach is to use an overhead projector for such displays.
One aspect of the invention is an interface that receives display data input from a calculator and outputs a video signal, for use by a video device such as a television. A processing unit and program memory cooperate to receive the display data from the calculator and to reformat the data as video data. The processing unit is also programmed to receive input from a pointing device, such as a mouse. Input data from the pointing device is processed so as to permit areas of the video image to be pointed to, highlighted, or otherwise manipulated.
Enhancements of the interface include the addition of a display of the keypad. The interface can be programmed so that the pointing device can be used to make selections from keypad display, thereby providing simulated operation of the calculator. The interface can be further programmed to provide a display of keystroke sequences.
An advantage of the invention is that it permits an instructor to point to areas on the television screen. This helps focus the attention of students on the matter being taught. Simultaneous display of the both calculator display and the keypad on the television screen helps students to better follow the instructor and to more effectively learn to use the calculator.